Memory is often incorporated into integrated circuitry. The memory may be used, for example, in computer systems for storing data.
Memory may be provided as a large array of memory cells. Wordlines and bitlines may be provided across the array such that individual memory cells may be uniquely addressed through the combination of a wordline and a bitline.
Numerous types of memory are available. An example class of memory is resistive random access memory (RRAM), which is of interest for utilization in existing and future data storage needs. RRAM utilizes programmable material having two or more stable states that differ in resistivity relative to one another. Example types of memory cells that may be utilized in RRAM are phase change memory (PCM) cells, programmable metallization cells (PMCs), conductive bridging random access memory (CBRAM) cells, nanobridge memory cells, electrolyte memory cells, binary oxide cells, and multilayer oxide cells (for instance, cells utilizing multivalent oxides). The memory cell types are not mutually exclusive. For example, CBRAM and PMC are overlapping classification sets.
A continuing goal of integrated circuit fabrication is to increase the level of integration (i.e., to scale circuitry to smaller dimensions). Wordlines and bitlines may become increasingly tightly packed across a memory array with increasing levels of integration. The wordlines and bitlines are electrically coupled with circuitry external to the memory array and are utilized to transfer electrical signals to and from the memory array during read/write operations. Difficulties are encountered in increasing the level of integration of memory in that it becomes increasingly difficult to make suitable connections from circuitry external of the memory array to the wordlines and bitlines. It is desired to develop new architectures suitable for making connections to wordlines and bitlines, and new methods of fabricating such architectures. It is also desirable for the architectures to be suitable for making connections to integrated circuit components other than wordlines and bitlines.